The invention relates to a composite, preservative-free utility pole, such as a light or telephone pole.
It is reported that the chemicals used as wood preservatives are known to be hazardous pesticides, yet are continuously used for wood utility poles. It is estimated that 135,000,000 such poles are in use in the United States. See “Poison Poles” 1997 Report by the National Coalition Against the Misuse of Pesticides (NCAMP). In another NCAMP report, “Pole Pollution,” a 1999 report, it is reported that pentachlorophenol, or “penta,” is a known carcinogen, but is still used in the U.S. for chemically treated wood utility poles. At the same time, penta is banned in 26 other countries.
For this reason, composite utility poles have been suggested in the prior art. For example, in Farber, U.S. Pat. No. 5,513,477, premolded external segments are suggested, which are combined in modular fashion for on-site assembly. Mirmiran et al. shows in U.S. Pat. No. 6,123,485, a fiber-reinforced plastic exterior shell with a concrete filling. Kubicky suggests in U.S. Pat. No. 6,322,863, a utility pole with internal reinforcing rods and a pipe column, where the utility pole is comprised of scrap rubber emulsion dispensed in a steel plate casing. Jernstrom suggests in U.S. Pat. No. 6,434,906, a post defined as a hollow, two-layer pole having an inner layer of fiber-reinforced thermo set plastic and an outer layer of polyolefin plastic. U.S. Pat. Nos. 6,397,545 and 6,453,635 also show extruded or “pultruded” utility poles and methods of making the same. These references are incorporated herein by reference.
As such, designs do not provide an adequate replacement for the wooden utility poles, preservative-based wooden poles continue to exist, and continue to be manufactured for use in the United States. Wooden poles have certain characteristics which require duplication, if a composite pole is to replace it. Thus, a composite pole would need to be easily manufactured, cost competitive with wooden poles, easily stored and transported, and provide similar characteristics when in use. For example, it is also desirable that the poles have an exterior surface allowing a utility worker to scale the pole for installation and maintenance of overhead wires. At the same time, it would be beneficial if the composite poles provided some benefits which were not available in the wooden poles.